In fairness, Morningstar and Value Line usually don't disagree sharply on a particular fund. They both make use of a five-point scale to grade risk-adjusted performance, and most of the discrepancies are only by one notch.

For example, Morningstar gives an above-average ranking of four stars to the Investment Co. of America, the nation's second-largest mutual fund (behind Fidelity Magellan). Value Line gives it a neutral rating of three.

Of the 25 biggest stock portfolios, only three have been given significantly different gradings by the two services. Both the Janus Fund and 20th Century Ultra enjoy Morningstar's top honor, a five-star rating, but they get only three from Value Line. Washington Mutual Investors gets an above-average mark from Morningstar but a below-average grade from Value Line.

Similarly, only three of the 25 biggest bond funds have significantly different ratings.

It's not surprising that the two systems deviate somewhat, considering they derive their numbers in different fashions. Morningstar calculates its total-return figures by weighting performance over three periods--10 years, five years and three years, in order of importance. Value Line, by contrast, looks only at the five-year numbers.

Both systems, it should be noted, can be misleading if a fund has recently lost the portfolio manager who established its track record.

Another difference deals with the way the sales charge, or load, is handled. Morningstar subtracts any sales charge from performance; Value Line doesn't.

To measure volatility, Morningstar uses a proprietary method that measures how well a fund fared compared to its peers and the "risk-free" return available on Treasury bills.

"Our system is a bit more tilted to favor the lower-risk funds," says John Rekenthaler, editor of Morningstar Mutual Funds. The rationale: Most investors are more worried about losing money than they are about upside fluctuations.

Value Line, by contrast, bases its risk measure on "standard deviation," a widely accepted yardstick that measures variability--up and down--in a fund's returns.

Notably, Morningstar in late April modified its methodology a bit, which has helped narrow the rating differential with Value Line slightly. A look at the same 200-plus funds using information available in early April showed the two services agreed on 40% of their ratings at that time.

Using another yardstick, the two services had differed by an average of 0.86 of a rating unit (Value Line doesn't use stars), but this gap has since narrowed to 0.62, Savage says.

This might be more detail than you want to know. The main point is that you should recognize that a single fund can get two different ratings, depending on which company is evaluating it. Also, ratings from either service can change over time, sometimes dramatically. Perhaps most important: Ratings describe past performance, not future results.

Consequently, Value Line and Morningstar caution investors not to place too much emphasis on a fund's rating, but rather to use it as an initial screening.

Digging beyond the ratings, investors will find a lot of similar information in the way both services evaluate funds. Both offer plenty of facts on performance, loads, other expenses, portfolio holdings, addresses, phone numbers and much more.